Hand-held surgical instruments

ABSTRACT

A hand-held surgical instrument includes a handle housing, an elongated shaft portion configured to extend distally relative to the handle housing, and a surgical end effector configured to be coupled to a distal end portion of the shaft portion. An articulation screw is operably coupled to the surgical end effector, and an articulation nut is disposed about and operably coupled to the articulation screw. The articulation screw is configured to translate in response to a rotation of the articulation nut, whereby the articulation screw articulates the surgical end effector between a parallel orientation relative to the shaft portion and a non-parallel orientation relative to the shaft portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63/084,656 filed Sep. 29, 2020, the entire disclosure of which is incorporated by reference herein.

BACKGROUND

A number of handle assembly manufacturers have developed product lines with proprietary drive systems for operating and/or manipulating electromechanical surgical instruments. In many instances the electromechanical surgical instruments include a handle assembly, which is reusable, and disposable loading units and/or single use loading units, such as, for example, surgical end effectors that are selectively connected to the handle assembly prior to use and then disconnected from the handle assembly following use in order to be disposed of or in some instances sterilized for re-use.

SUMMARY

In one aspect of the present disclosure, a hand-held surgical instrument is provided and includes a handle housing defining a cavity therein, an elongated shaft portion configured to extend distally relative to the handle housing, a surgical end effector configured to be coupled to a distal end portion of the shaft portion and configured to articulate relative to the shaft portion, a fire shaft, an articulation screw, and an articulation nut. The fire shaft has a proximal end portion configured to be drivingly coupled to a driver, and a distal end portion configured to be operably coupled to a driven element of the surgical end effector. The articulation screw is operably coupled to the surgical end effector, and the articulation nut is disposed about and operably coupled to the articulation screw. The articulation screw is configured to translate in response to a rotation of the articulation nut, whereby the articulation screw articulates the surgical end effector between a parallel orientation relative to the shaft portion and a non-parallel orientation relative to the shaft portion.

In aspects, the articulation nut may be axially restrained to and rotatably supported by the handle housing. The articulation screw may be received within the articulation nut.

In aspects, the articulation nut may be threadedly coupled to an outer surface of the articulation screw such that rotation of the articulation nut in a first rotational direction distally or proximally translates the articulation screw. Rotation of the articulation nut in a second, opposite rotational direction the other of distally or proximally translates the articulation screw.

In aspects, each of the articulation screw and articulation nut may have a tubular configuration.

In aspects, the articulation screw and the articulation nut may be concentrically disposed about the fire shaft.

In aspects, the hand-held surgical instrument may further include an articulation knob disposed about the articulation nut and rotationally fixed to the articulation nut such that a manual rotation of the articulation knob may rotate the articulation nut.

In aspects, the articulation knob may be connected to or monolithically formed with the articulation nut.

In aspects, the hand-held surgical instrument may further include an articulation link having a proximal end portion axially fixed to the articulation screw. The articulation link may have a distal end portion configured to be operably coupled to the surgical end effector.

In aspects, the articulation link may have a pin extending laterally outward from the proximal end portion thereof. The pin may be fixed to a distal end portion of the articulation screw.

In aspects, the hand-held surgical instrument may further include a fire nut threadedly coupled to the fire screw and configured to translate in response to a rotation of the fire screw to effectuate a stapling function of the surgical end effector.

In aspects, the hand-held surgical instrument may further include a fire rod extending through the shaft portion. The fire rod may have a proximal end portion fixed to the fire nut, and a distal end portion coupled to the driven element of the surgical end effector.

In aspects, the hand-held surgical instrument may further include a tube housing axially restrained to the handle housing. The fire nut may be disposed within and keyed to the tube housing to resist relative rotation between the fire nut and the tube housing.

In aspects, the hand-held surgical instrument may further include an instrument module configured for receipt in the cavity of the handle housing. The instrument module may include a motor and the driver. The driver may be operably coupled to the motor and configured to operably couple to the proximal end portion of the fire shaft such that rotation of the driver results in rotation of the fire shaft.

In aspects, the hand-held surgical instrument may further include a button coupled to the handle housing, and a printed circuit board. The button may be associated with the printed circuit board such that an actuation of the button activates the motor.

In accordance with further aspects of the disclosure, a disposable handle assembly of a hand-held surgical instrument is provided and includes an elongated handle housing defining a cavity therein, an articulation nut rotatably supported by a distal end portion of the handle housing, an articulation screw received within the articulation nut and threadedly coupled to the articulation nut, and an articulation knob disposed about the articulation nut and rotationally fixed to the articulation nut such that a manual rotation of the articulation knob rotates the articulation nut to translate the articulation screw relative to the articulation nut.

In aspects, the articulation screw may define an elongated passageway therethrough.

In aspects, the disposable handle assembly may further include an articulation link having a proximal end portion disposed within the passageway and axially fixed to the articulation screw.

In aspects, the articulation link may have a pin extending laterally outward from the proximal end portion thereof. The pin may be fixed to a distal end portion of the articulation screw.

In aspects, the disposable handle assembly may further include a fire shaft having a proximal end portion received in the cavity of the handle housing. The articulation screw and the articulation nut may be concentrically disposed about the fire shaft.

In aspects, the articulation knob may be connected to or monolithically formed with the articulation nut.

As used herein, the terms parallel and perpendicular are understood to include relative configurations that are substantially parallel and substantially perpendicular up to about + or −10 degrees from true parallel and true perpendicular.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein:

FIG. 1A is a side perspective view illustrating a hand-held electromechanical surgical instrument including a handle assembly, a shaft portion coupled to the handle assembly, and a surgical end effector coupled to the shaft portion;

FIG. 1B is a side perspective view illustrating the hand-held electromechanical surgical instrument of FIG. 1A, with a power assembly shown separated from the handle assembly;

FIG. 2 is a perspective view, with parts separated, illustrating the surgical instrument of FIG. 1A;

FIG. 3 is an enlarged perspective view illustrating components of the surgical instrument of FIG. 1A including an articulation knob, a fire shaft, and PCB connection;

FIG. 4 is a longitudinal cross-sectional view of the surgical instrument of FIG. 1A; and

FIG. 5 is a longitudinal cross-sectional view of the surgical instrument of FIG. 1A including a manually operated articulation assembly and a motor-powered fire assembly disposed within the articulation assembly.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instruments including handle assemblies thereof are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein the term “distal” refers to that portion of the surgical instrument, or component thereof, farther from the user, while the term “proximal” refers to that portion of the surgical instrument, or component thereof, closer to the user.

As will be described in detail below, provided is a handle assembly of a hand-held surgical instrument having an ergonomic, disposable handle housing, a reusable power assembly (e.g., an instrument module housed within a sterile or non-sterile outer casing), a shaft portion extending distally from the handle housing, and a surgical end effector pivotably coupled to a distal end of the shaft portion. It is contemplated that all components of the surgical instrument other than the power assembly are disposable.

The surgical instrument has a manual articulation knob disposed between the handle housing and the shaft portion and configured to rotate relative thereto. The articulation knob is rotationally fixed about an articulation nut, which is threadedly coupled to an articulation screw. The articulation screw supports an axially-translatable articulation link that operably couples to the surgical end effector to articulate the surgical end effector relative to the shaft portion in response to a manual rotation of the articulation knob. A fire assembly, configured to effectuate an opening/closing and stapling function of the surgical end effector, extends coaxially through the articulation assembly and is actuated by the power assembly. Other features and benefits of the disclosed surgical instruments are further detailed below.

With reference to FIGS. 1A, 1B, 2, and 3, a surgical instrument, in accordance with an embodiment of the present disclosure, is generally designated as 10, and is in the form of a powered hand-held electromechanical surgical instrument for actuating and manipulating a surgical end effector 200. The hand-held electromechanical surgical instrument 10 includes a handle assembly 12, an articulation knob housing 14 coupled to the handle assembly 12, and a shaft portion 16 extending distally from the articulation knob housing 14 and having the end effector 200 attached thereto.

The handle assembly 12 includes a disposable and sterile elongated handle housing 18 and a hinged door 20 pivotably coupled to a proximal end portion 18 a of the handle housing 18. The door 20 is selectively opened and closed to allow for the insertion or removal of a non-sterile, reusable instrument module or power assembly 22. The handle housing 18 and the door 20 each have an inner periphery collectively defining an internal cavity 17 for the instrument module 22 upon closing the door 120. In aspects, the proximal end portion 18 a or any suitable location of the handle housing 18 may have a clear window (not shown) to allow for viewing of a display (e.g., an LCD, not shown).

The handle assembly 12 has a fire/closing switch 24 a and an opening switch 24 b. The fire switch 24 a is configured and adapted to close jaw members 206, 208 of the end effector 200 and ultimately effectuate a stapling function of the end effector 200. The opening switch 24 b is configured to open the jaw members 206, 208 of the end effector 200. The switches 24 a, 24 b may be constructed as buttons movably coupled to the handle housing 18 at a location proximal and adjacent the articulation knob housing 14. An activation of the fire switch 24 a activates a motor 25 of the instrument module 22 to advance or retract a firing rod 44 (FIGS. 4 and 5) of the surgical instrument 10 depending on whether switch 24 a or switch 24 b is actuated. The firing rod 44 is coupled to a driven element (not explicitly shown) of the end effector 200 (which includes a knife rod and an actuation sled), such that advancement of the firing rod 44 advances the driven element of the end effector 200, which closes the jaw members 206, 208 of the end effector 200 and fires the end effector 200 when a safety switch 28 is in an actuated state.

For a detailed discussion of the construction and operation of the surgical end effector 200, reference may be made to U.S. Pat. No. 7,819,896, filed on Aug. 31, 2009, entitled “TOOL ASSEMBLY FOR A SURGICAL STAPLING DEVICE,” U.S. Pat. No. 8,066,166, filed Apr. 5, 2007, entitled “SURGICAL STAPLING DEVICE WITH DISSECTING TIP,” and U.S. Pat. No. 9,820,741, filed May 12, 2011, entitled “REPLACEABLE STAPLE CARTRIDGE,” the entire contents of each of which being incorporated by reference herein.

The safety switch 28 is constructed as a tactile switch extending transversely through the handle housing 18. The safety switch 28 has opposing end portions exposed from an outer surface of the handle housing 18 to allow a clinician to slide the safety switch 28 between a firing-disabled position and a firing-enabled position. In the firing-disabled position, the safety switch 28 either contacts or disengages a contact switch 30 (FIG. 3) on a printed circuit board 32 (FIG. 3) of the handle assembly 12, whereby a processor (not explicitly shown) of the instrument module 22 is signaled to prevent an activation of the motor 25 notwithstanding an actuation of the fire switch 24 a. In the firing-enabled position, the safety switch 28 contacts or disengages the contact switch 30, whereby the processor is signaled to allow an activation of the motor 25 upon actuating the fire switch 24 a. In aspects, the safety switch 28 may have a light therein configured to blink or remain on in a steady state to indicate the position of the safety switch 28.

In some embodiments, the switches 24 a, 24 b, 28 of the handle assembly 12 may be assigned to actuate various functions to be carried out by various surgical end effectors. It is contemplated that the switches 24 a, 24 b, 28 can be variously configured, such as, for example, as switches, rockers, flaps, latches, levers, dials, buttons, or touch screens.

The reusable instrument module or power assembly 22 of the handle assembly 12 includes the motor 25, such as, for example, an electrical drive motor, which is drivingly coupled to an output 27, such as, for example, a socket and/or a pinion gear. The motor 25 is electrically connected or wirelessly connected to the motor controller or processor and a battery (not explicitly shown). In aspects, the battery may include a boost circuit and may be rechargeable (e.g., wirelessly). The battery has a card edge connector (not explicitly shown) configured for detachable receipt of a card edge header 34 of the printed circuit board 32 to allow for communication from the switches 24 a, 24 b and the safety switch 28 to the battery. The processor may include a USB charging connector to allow for the battery to be recharged with a USB charger or wirelessly (e.g., via induction).

Further details about the instrument module 22 may be found in U.S. Provisional Patent Application No. 63/064,977, filed on Aug. 13, 2020, incorporated by reference above.

With reference to FIGS. 2-5, the surgical instrument 10 further includes a fire assembly 40 for driving the opening/closing and stapling function of the surgical end effector 200, and an articulation assembly 50 for driving an articulation of the surgical end effector 200. The fire assembly 40 generally includes a fire shaft 42, such as, for example, a lead screw, a fire nut 43, and a fire rod 44. The fire shaft 42 extends distally from the handle housing 18, through the articulation knob housing 14, and into a proximal end portion 16 a of the shaft portion 16. The fire shaft 42 has a proximal end portion 42 a protruding proximally into the cavity 17 of the handle housing 18 to non-rotatably connect to the output 27 (FIG. 1B) of the instrument module 22 when the instrument module 22 is received in the cavity 17. The proximal end portion 42 a of the fire shaft 42 may have a tri-lobe configuration and the output 27 may have a correspondingly shaped socket to form the non-rotatable connection therebetween. Other types of non-rotatable connections are also contemplated, such as a bayonet type connection. A thrust bearing and a seal may be provided between the proximal end portion 42 a of the fire shaft 42 and a distal end portion 18 b of the handle housing 18.

The fire nut 43 is disposed about the fire shaft 42 and is threadedly coupled to the fire shaft 42 such that the fire nut 43 translates either proximally or distally depending on the direction of rotation of the fire shaft 42. The fire nut 43 is elongated and has a non-circular cross-sectional configuration, such as, for example a D-shaped configuration. Other cross-sectional configurations are contemplated for the fire nut 43, such as, for example, rectangular, triangular, or the like.

The fire nut 43 is keyed to a correspondingly shaped inner surface 46 of a tubular housing 48 to prevent rotation of the fire nut 43 within the tubular housing 48 or by the fire shaft 42 as the fire shaft 42 rotates. The tubular housing 48 has a proximal end portion 48 a (FIG. 5) axially and rotatably restrained within a pocket 49 defined in the distal end portion 18 b of the handle housing 18. The tubular housing 48 has a distal end portion 48 b supported between the proximal end portion 16 a of the shaft portion 16 and the distal end portion of the knob housing 14.

The fire rod 44 has a proximal end portion 44 a fixed to a distal end portion 43 b of the fire nut 43. The fire rod 44 extends distally through the shaft portion 16 terminating in a distal end portion (not explicitly shown) that is coupled to the driven element of the surgical end effector 200.

With reference to FIGS. 2, 4, and 5, the articulation assembly 50 of the handle assembly 12 is configured to actuate an articulation of the end effector 200 (e.g., move the end effector 200 along a horizontal plane between a position coaxial with the shaft portion 16 and multiple positions out of alignment with the shaft portion 16). The articulation assembly 50 includes the knob housing 14, an articulation nut 52, and an articulation screw 54. The articulation knob or knob housing 14 is rotatably coupled to the handle housing 18 at a proximal end 14 a and rotatably coupled to the shaft portion 16 at a distal end 14 b.

The articulation nut 52 has a proximal end portion 52 a received in the distal end portion 18 b of the handle housing 18. The proximal end portion 52 a of the articulation nut 52 is rotatably supported while being axially restrained by the distal end portion 18 b of the handle housing 18. The articulation knob 14 is disposed about the articulation nut 52 and rotationally fixed to the articulation nut 52 such that a manual rotation of the articulation knob 14 rotates the articulation nut 52. In aspects, the articulation knob 14 may be connected to, monolithically formed with, or otherwise coupled to the articulation nut 52.

The articulation screw 54 has a proximal end portion 54 a received within the articulation nut 52 and threadedly coupled to a threaded inner surface 56 of the articulation nut 52. The articulation screw 54 is configured to translate relative to the articulation nut 52 either proximally or distally depending on the direction of rotation of the articulation nut 52. The articulation screw 54 defines an elongated passageway 56 (FIG. 2) therethrough. The fire assembly 40 is disposed concentrically within passageway 56 of the articulation screw 54, and the articulation screw 54 is disposed concentrically within the articulation nut 52, thereby providing a compact assembly of these components.

The articulation assembly 50 further includes an articulation link 58 having a proximal end portion 58 a disposed within the passageway 56 of the articulation screw 54 in a space 60 (FIG. 5) defined between the inner surface 46 of the tubular housing 48 and an outer surface of the fire nut 43. The proximal end portion 58 a of the articulation link 58 has a pin 62 extending laterally outward therefrom. The pin 62 extends through a lateral opening 64 in the tubular housing 48 and is fixed to a distal end portion 54 b of the articulation screw 54, thereby axially fixing the articulation link 58 to the articulation screw 54. The distal end portion 54 b of articulation screw 54 may be non-rotatably secured to the tubular housing 48 via a fastener 66 to resist rotation of the articulation screw 54 during rotation of the articulation nut 52.

The articulation link 58 has a distal end portion (not explicitly shown) coupled to a pivotable link (not explicitly shown) pivotably supported in the distal end portion 16 b of the shaft portion 16. The pivotable link pivotably couples the articulation link 58 and the surgical end effector 200 to one another such that a distal translation of the articulation link 58 causes the pivotably link to articulate the surgical end effector 200 relative to the shaft portion 16 in a first direction, and a proximal translation of the articulation link 58 causes the pivotable link to articulate the surgical end effector 200 relative to the shaft portion 16 in the opposite, second direction.

For further details about the mechanism that pivotably couples the surgical end effector to the shaft portion, reference may be made to U.S. patent application Ser. No. 16/695,380, filed on Nov. 26, 2019, the entire contents of which are incorporated by reference herein.

In operation, the instrument module 22 is inserted into the handle housing 18 and the door 20 is closed, thereby sealing the non-sterile, reusable instrument module 22 in the sterile handle housing 18. The card edge head 34 of the printed circuit board 32 of the handle assembly 12 is connected to the card edge connector of the instrument module 22. Upon properly inserting the instrument module 22, the output 27 (FIG. 1B) of the instrument module 22 drivingly couples to the proximal end portion 42 a of the fire shaft 42.

To operate the surgical end effector 200, the button 24 a may be actuated, whereby the battery of the instrument module 22 provides power to the motor 25, which drives a rotation of the output 27. As the output 27 rotates in a first direction, the fire shaft 42 is caused to rotate to drive a translation of the drive nut 43 and the attached fire rod 44. The translation of the fire rod 44 results in the closing of the jaw members 206, 208. To open the jaw members 206, 208, button 24 b may be actuated instead. To fire staples from the surgical end effector 200, with the jaw members 206, 208 in the closed state, the safety switch 28 is actuated, and then the button 24 a may be actuated, whereby the driven element (e.g., a stapling sled) of the surgical end effector 200 translates through the jaw member 208 (e.g., a cartridge assembly) to fire the staples into tissue.

To articulate the surgical end effector 200 towards the right (from the perspective of the clinician), the articulation knob housing 14 is manually rotated clockwise (from the perspective of the clinician), which transfers rotational motion from the knob housing 14 to the articulation nut 52. Rotation of the articulation nut 52 drives a proximal translation of the articulation screw 54 relative to the articulation nut 52, whereby the articulation link 58 is driven proximally to articulate the surgical end effector 200. Similarly, to articulate the surgical end effector 200 to the left, the articulation knob housing 14 may be manually rotated counter-clockwise. As such, manual actuation of the articulation knob housing 14 moves the surgical end effector 200 from a first position corresponding to a non-articulated orientation of the surgical end effector 200 (i.e., the surgical end effector 200 is coaxial with the shaft portion 16) to a second position corresponding to an articulated orientation of the surgical end effector 200 (i.e., the surgical end effector 200 is pivoted to a non-parallel angle relative to the shaft portion 16). In aspects, rotation of the knob housing 14 may be accomplished electronically or robotically.

Any of the components described herein may be fabricated from either metals, plastics, resins, composites or the like taking into consideration strength, durability, wearability, weight, resistance to corrosion, ease of manufacturing, cost of manufacturing, and the like. Any of the gears disclosed herein may be configured as any suitable gear, such as bevel gears, spur gears, spiral gears, worm gears, or the like.

It will be understood that various modifications may be made to the embodiments of the presently disclosed surgical instruments including switch assemblies. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. 

What is claimed is:
 1. A hand-held surgical instrument, comprising: a handle housing defining a cavity therein; an elongated shaft portion configured to extend distally relative to the handle housing; a surgical end effector configured to be coupled to a distal end portion of the shaft portion and configured to articulate relative to the shaft portion; a fire shaft having a proximal end portion configured to be drivingly coupled to a driver, and a distal end portion configured to be operably coupled to a driven element of the surgical end effector; an articulation screw operably coupled to the surgical end effector; an articulation nut disposed about and operably coupled to the articulation screw, wherein the articulation screw is configured to translate in response to a rotation of the articulation nut, whereby the articulation screw articulates the surgical end effector between a parallel orientation relative to the shaft portion and a non-parallel orientation relative to the shaft portion; a tubular housing axially and rotatably restrained within the handle housing and extending within the articulation screw, the shaft portion having a proximal end portion coupled to a distal end portion of the tubular housing; and a fire nut threadedly coupled to the fire shaft and configured to translate in response to a rotation of the fire shaft to effectuate a stapling function of the surgical end effector, wherein the fire nut is disposed within and coupled to the tubular housing to resist relative rotation between the fire nut and the tubular housing.
 2. The hand-held surgical instrument according to claim 1, wherein the articulation nut is axially restrained to and rotatably supported by the handle housing, and the articulation screw is received within the articulation nut.
 3. The hand-held surgical instrument according to claim 1, wherein the articulation nut is threadedly coupled to an outer surface of the articulation screw such that rotation of the articulation nut in a first rotational direction one of distally or proximally translates the articulation screw, and rotation of the articulation nut in a second, opposite rotational direction the other of distally or proximally translates the articulation screw.
 4. The hand-held surgical instrument according to claim 1, wherein each of the articulation screw and articulation nut has a tubular configuration.
 5. The hand-held surgical instrument according to claim 4, wherein the articulation screw and the articulation nut are concentrically disposed about the fire shaft.
 6. The hand-held surgical instrument according to claim 1, further comprising an articulation knob disposed about the articulation nut and rotationally fixed to the articulation nut such that a manual rotation of the articulation knob rotates the articulation nut.
 7. The hand-held surgical instrument according to claim 6, wherein the articulation knob is connected to or monolithically formed with the articulation nut.
 8. The hand-held surgical instrument according to claim 1, further comprising an articulation link having a proximal end portion axially fixed to the articulation screw and received in a space defined between an inner surface of the tubular housing and an outer surface of the fire nut, and a distal end portion configured to be operably coupled to the surgical end effector.
 9. The hand-held surgical instrument according to claim 8, wherein the articulation link has a pin extending laterally outward from the proximal end portion thereof, the pin being fixed to a distal end portion of the articulation screw.
 10. The hand-held surgical instrument according to claim 1, further comprising a fire rod extending through the shaft portion and having a proximal end portion fixed to the fire nut, and a distal end portion coupled to the driven element of the surgical end effector.
 11. The hand-held surgical instrument according to claim 1, further comprising an instrument module configured for receipt in the cavity of the handle housing and including: a motor; and the driver operably coupled to the motor and configured to operably couple to the proximal end portion of the fire shaft such that rotation of the driver results in rotation of the fire shaft.
 12. The hand-held surgical instrument according to claim 11, further comprising: a button coupled to the handle housing; and a printed circuit board, the button associated with the printed circuit board such that an actuation of the button activates the motor.
 13. A disposable handle assembly of a hand-held surgical instrument, the disposable handle assembly comprising: an elongated handle housing defining a cavity therein; an articulation nut rotatably supported by a distal end portion of the handle housing; an articulation screw received within the articulation nut and threadedly coupled to the articulation nut; an articulation knob disposed about the articulation nut and rotationally fixed to the articulation nut such that a manual rotation of the articulation knob rotates the articulation nut to translate the articulation screw relative to the articulation nut; a tubular housing axially and rotatably restrained within the handle housing and extending within the articulation screw; a fire screw extending through the tubular housing and having a proximal end portion configured to be drivingly coupled to a driver, and a distal end portion configured to be operably coupled to a driven element of a surgical end effector; and a fire nut threadedly coupled to the fire screw and configured to translate in response to a rotation of the fire screw to effectuate a stapling function of the surgical end effector, wherein the fire nut is disposed within and keyed to the tubular housing to resist relative rotation between the fire nut and the tubular housing.
 14. The disposable handle assembly according to claim 13, wherein the articulation screw defines an elongated passageway therethrough.
 15. The disposable handle assembly according to claim 14, further comprising an articulation link having a proximal end portion disposed within the passageway and axially fixed to the articulation screw.
 16. The disposable handle assembly according to claim 15, wherein the articulation link has a pin extending laterally outward from the proximal end portion thereof, the pin being fixed to a distal end portion of the articulation screw.
 17. The disposable handle assembly according to claim 13, wherein the articulation screw and the articulation nut are concentrically disposed about the fire screw.
 18. The disposable handle assembly according to claim 13, wherein the articulation knob is connected to or monolithically formed with the articulation nut. 